Question

the exterior angles of a triangle are 3y,4y and 5y.find the smallest interior angle of the triangle

Answer 1

sum of the exterior angles of a triangle is 360

$3y + 4y + 5y = 360 \\ 12y = 360 \\y = \frac{360}{12} \\ y = 30$

then

3y=3(30)=90

4y=4(30)=120

5y=5(30)=150

then the smallest interior angle is 210